While not necessarily limited thereto, the present invention relates to longwall mining machinery for working thick seams in underground mining, and more particularly in pillar clearance or in driving large rise headings. In the past, systems such as that shown in German Offenlegungsschrift No. 2,509,810 have been provided in which both a bottom frame and a top frame extend along the longwall mining face. A face conveyor and a longwall mining machine are provided for both the bottom frame and the top frame of the system, the bottom machine removing the mineral seam down to the floor and the top machine removing the seam up to the roof, in each case through the agency of a shearer drum carried by a pivoted arm.
Facilities of the kind described above can be used only for longwall working and even in this connection only for relatively thick seams. Furthermore, they cannot be used to drive a large rise heading or to clear pillars. They are expensive to build and elaborate since they can be operated only with the two double drum-cutter loader machines which require clearance at both face ends beyond the end of the support system. An elaborate system of this type is uneconomical for driving large rise headings or clearing pillars, if for no other reason than the complex machinery needed for the facility.